The present invention relates to novel compositions which are useful in cosmetology, in particular shampoos and foaming gels, which are intended to care for the hair and/or the scalp, in particular to combat dandruff or to prevent its formation. The invention is directed towards shampoos whose washing base contains an amphoteric surfactant and an anionic surfactant, where appropriate supplemented with a thickener and/or a hair conditioner.
In shampoos whose washing base contains an anionic surfactant and an amphoteric surfactant, the washing function itself is based on the two components, but a foaming function is provided by the amphoteric surfactant. In very general terms, the amphoteric surfactant is an alkylbetaine, in particular a lauric-, coconut- or palm kernel-based alkylamidopropylbetaine. The mechanical elimination of dandruff, the causative agent of which is a fungus, Pityrosporum ovalae, is one of the expected results of shampooing, but it has also been sought to develop shampoos which combat or prevent the formation of dandruff. For this, use has been made of various antifungal agents.
Among the standard antifungal agents, mention may be made of:
preserving agents whose fungal spectrum is oriented towards fungi and particularly yeasts, such as sorbic acid and dehydroacetic acid,
active agents listed as anti-yeast agents, such as zinc pyrithione, piroctone-olamine and climbazole,
a few surfactants derived from undecylenic acid, in particular 4-sulpho-{2-[(1-oxo-10-undecenyl)amino]ethyl}butanedioic ester, disodium (RN=26650-05-5) (or disodium undecylenamido MEA sulphosuccinate, according to the CTFA name adopted in the International Cosmetic Ingredient Dictionary, 6th edition, by The Cosmetics, Toiletry and Fragrance Association, 1995), and N-(2-hydroxyethyl)undecenamide (RN=20545-92-0 and 40839-40-5) (CTFA : undecylenamide MEA).
However, some antifungal active principles among those most commonly used show cytotoxic potential in vitro. It is necessary to lower the working amounts thereof to below an acceptable cytotoxicity threshold, or even to combine them with molecules which protect the integrity of skin cells which are damaged or inflamed to a greater or lesser extent. These products have other drawbacks: for example, piroctone-olamine poses coloration problems in shampoos containing this active principle, zinc pyrithione is a water-insoluble powder which leads to opaque formulations that are unstable in light, climbazole is water-insoluble and requires the mandatory use of solvents (ethanol, benzyl alcohol).
As regards the undecylenic acid derivatives, some have already been cited for their antibacterial and antifungal activity, in particular the zinc salts of undecylenamido MEA sulphosuccinate (WO 97/18823 of 29.05.97 from Pixc3xa8rre Fabre; EP 23676 of 11.02.81 from Rewo) and of tricarboxylic acid which are derived from the product of the Diels-Alder reaction between maleic anhydride and undecylenic acid (EP 71025 of 9.02.83 from Grillo Werke AG), as well as a number of esters (JP 08/053,326 of 27.02.96 from Kanebo; EP 28459 of 13.05.81 from Imperial Chemical Industries Ltd.). As examples, among the most common undecylenic acid derivatives are found N-(2-hydroxyethyl)undecenamide (CTFA : undecylenamide MEA) and 4-sulpho-{2-[(1-oxo-10-undecenyl)amino]ethyl}butanedioic ester, disodium (CTFA: disodium undecylenamido MEA sulphosuccinate), which are sold, respectively, under the trade names xe2x80x9cRewocid(copyright)U185 or Witcamide(copyright)6570xe2x80x9d and xe2x80x9cRewocid(copyright)SB U185xe2x80x9d by the company Witco. However, these derivatives are not amphoteric.
It has been discovered, unexpectedly, that in addition to the usual characteristics of betaines (co-surfactant, good foaming power, mild detergent), N-(carboxymethyl)-N,N-dimethyl-3-[(1-oxoundecenyl)amino]-1-propanaminium hydroxide (RN=98510-75-9, neutral zwitterionic form) or CTFA: undecylenamidopropylbetaine 
has antifungal activity towards Pityrosporum ovalae and thus develops antidandruff efficacy which has never been cited to date. Consequently, it offers the very great advantage of being able to constitute an amphoteric component of a shampoo which itself has the desired antidandruff properties. This discovery is exploited in shampoos of the invention, which are essentially aqueous compositions of a washing base consisting of amphoteric surfactants and anionic surfactants and whose amphoteric surfactants do themselvesxe2x80x94and this is the characteristic of the inventionxe2x80x94partly consist of undecylenamidopropylbetaine.
For the purposes of the invention, the term anionic surfactant is understood to refer to one or more compounds taken from the group formed of (C10 to C14)alkyl sulphates and (C10 to C14)alkyl ether sulphates. Lauryl ether sulphates are anionic surfactants used commonly by shampoo formulators.
For the purposes of the invention, the term amphoteric surfactant is understood to refer to the compounds chosen, alone or as a mixture, from alkyl amphocarboxyglycinates, alkyl amphocarboxypropionates, alkyl amphodiacetates, alkyl amphodipropionates, alkyl amphoglycinates, alkyl amphopropionates, alkyl iminopropionates, alkyl iminodipropionates, alkyl amphopropylsulphonates, alkylbetaines, alkylamidopropylbetaines, alkylsultaines and alkylamidopropylhydroxysultaines. In this list, alkyl is understood in the sense of C10 to C14 hydrocarbon-based chains and more especially lauric, coconut or palm kernel fatty acid residues or equivalent sources. Cocoamidopropylbetaines are amphoteric compounds that are preferred for preparing the formulations according to the invention.
Undecylenamidopropylbetaine, which is the characteristic amphoteric compound of the invention, is an undecylenic-based alkylamidopropylbetaine. It can be prepared according to processes known to those skilled in the art, in particular by following the procedure described in U.S. Pat. No. 3,225,074 (American Cyanamid) which consists in reacting undecylenic acid with N,N-dimethyl-1,3-propanediamine (DMAPA) between 140 and 200xc2x0 C., followed by reacting the tertiary amidoamine 
thus obtained with monochloroacetic acid in the presence of an alkaline salt or the corresponding salt of this acid, the reaction being carried out in aqueous medium. The alkali metal chloride, usually sodium chloride, co-produced during the reaction is generally left in this aqueous betaine solution.
The compositions of the invention are aqueous solutions in which the content of all of the constituents of the washing base (amphoteric and anionic compounds) lies within certain limits so as to ensure their physical equilibrium, in particular their homogeneity and their transparency (in the absence of the intentional introduction of pearlescent agents), these limits naturally being capable of varying to a certain extent depending on the individual components used, which will be represented by the following symbols: An used for anionic components, Amph for amphoteric compounds, xcexa3Amph representing all of the amphoteric compounds, AmphU representing undecylenic betaine, Amph* representing the amphoteric components except for undecylenic betaine.
This gives, on the one hand, as regards the anionic components/amphoteric compounds equilibrium:
12.5%xe2x89xa6An+xcexa3Amphxe2x89xa617.6
5%xe2x89xa6Anxe2x89xa615
3.5%xe2x89xa6xcexa3Amphxe2x89xa69.2
on the other hand, as regards the amphoteric compounds/undecylenic amphoteric component equilibrium:
3.5%xe2x89xa6xcexa3Amphxe2x89xa69.2
2%xe2x89xa6Amph*xe2x89xa67
1.5%xe2x89xa6AmphUxe2x89xa63.5
A common shampoo composition according to the invention will have, for example, the general composition
The common ingredients in the formulation of products of this type form part of these compositions, namely:
thickeners intended to give the shampoos a sufficient consistency and improved cosmetic qualities. Among the known thickeners, carbomers (acrylic acid homopolymers crosslinked with an allylic ether of pentaerythritol, of sucrose or of propylene), PEG esters, laurylpyrrolidone, acrylic copolymers and cationic polymers of natural or synthetic origin, including certain polyquaternium compounds (see the conditioners below) give very satisfactory results in the application considered, in particular bearing in mind that viscosities of greater than 1000 mPa.s, preferably between 1000 mPa.s and 30,000 mPa.s, could be obtained with these specific products (xe2x80x9cCarbopol Ultrez(copyright)10xe2x80x9d from BF Goodrich, xe2x80x9cAtlas(copyright)G-1821xe2x80x9d from ICI, xe2x80x9cSurfadone(copyright)LP 300xe2x80x9d from ISP, xe2x80x9cAcrysol(copyright)22xe2x80x9d from Rohm and Haas, xe2x80x9cJaguar(copyright)C 162xe2x80x9d and xe2x80x9cRhodicare(copyright)Txe2x80x9d from Rhxc3x4ne-Poulenc, xe2x80x9cUcare(copyright)Polymer Jr. 400xe2x80x9d from Amerchol, xe2x80x9cMackernium(copyright)7xe2x80x9d from Jan Dekker/MacIntyre and xe2x80x9cGafquat(copyright)755 Nxe2x80x9d from ISP). These specific thickeners make it possible to obtain acceptable viscosities when they are used at concentrations of between 0 and 4% by weight relative to the whole composition, preferably between 0.2 and 2% by weight.
Conditioners, these being products intended to improve the cosmetic properties of detergent solution, generally cationic or amphoteric polymers, oils, and in particular silicones or silicone derivatives, the compatibility of which with all of the other constituents of the formulation should be checked, and in particular in order to avoid the formation of cosmetically unacceptable cloudy gels; in this respect, it has been found that the use of cationic polymers such as polyquaternium-7 (in particular xe2x80x9cMackernium 7xe2x80x9d from Jan Dekker/MacIntrye), polyquaternium-10 (in particular xe2x80x9cUcare Polymer JR 400xe2x80x9d from Amerchol) and polyquaternium-11 (in particular xe2x80x9cGafquat 755 Nxe2x80x9d from ISP) at concentrations of about 1 to 4%, allow entirely clear gels to be conserved.
Foam enhancers/stabilizers, these being compounds taken from the group consisting of diethanolamine alkanolamide or tertiary amine oxides, which can be used at contents of between 1 and 5% by weight relative to the total weight of the composition, but which are increasingly tending to be left out of the formulation for fear of the toxicity induced by some of their possible impurities.
The compositions can also contain certain adjuvants that are common in the shampoo sector, preserving agents, sequestering agents, softeners, foam modifiers, dyes, pearlescent agents, moisturizers, antiseborrhoeic agents, vitamins, sunscreens and fragrances. As regards the fragrances in the formulation, it should be pointed out that the low characteristic odour of undecenylamidopropylbetaine permits any fragrance, from the most discreet to the most specific.
The use, alone or as a mixture, of common preserving agents such as phenoxyethanol, methylparaben, ethylparaben, propylparaben and butylparaben (CTFA nomenclatures, INCI, 6th edition) at concentrations of between 0.25% and 1% by weight relative to the whole composition, has proven to be particularly useful for obtaining effective and long-lasting protection of foaming gels.
The compositions according to the invention can also contain additional solvents, for example glycols or glycerol, which, at concentrations of between 2% and 8% by weight, and even more particularly between 4% and 6% by weight, relative to the whole composition, improve the physical stability of the formulations at low temperatures (problems of clouding or of crystal growth in particular) and promote rapid penetration of the active principle into the horny layer and improve the condition of irritated horny layer (hydration of the surface epidermal layers of the scalp).
The pH of these compositions must be between 4.5 and 7.0, especially around 6, in order for the antifungal activity to be preserved at the optimum level. Adjustment of the pH to the desired value is conventionally carried out by addition of an organic or inorganic acid or base, for example citric acid, succinic acid, phosphoric acid, sodium hydroxide or sodium carbonate.
The washing and antifungal compositions according to the invention are stable (absence of decantation or of demixing of phases) and homogeneous over time within a temperature range between 4 and 45xc2x0 C., both in natural light and under our Sun Test ageing conditions. They are well tolerated by the skin. They also have good foaming and washing power, which allows the removal of dandruff and good rinsability. Their viscosity must be sufficient for them to be easy to measure out in the hand. In practice, their viscosity must be greater than 1000 mPa.s.
The formulations according to the invention can be used for the preparation of more or less viscous, very faintly coloured transparent products of liquid or gel texture.
The gel forms are preferred for the curative, topical-route treatment of dandruff, these forms being used as shampoos, i.e. they are applied to the skin, the hair and/or the scalp for a few minutes, and then rinsed with water.